Impact of electric voltages on the emulsification capabilities of okra seed protein-rich extract

A portion of okra seed protein-rich extract (PRE) prepared with NaCl solution (5 g/L) was hydrolyzed at 110°C for 5 h (1 atm. pressure). The PRE (sample A), hydrolyzed PRE-B, whole okra seed flour-C and gelatin-D were tested for emulsification capacity (EMC) and emulsion stability (ES). The emulsions were prepared and tested in (i) normal environmental condition (o/w and w/o), (ii) current carrying beaker-CB, (iii) Ohmic heating beaker-OB. The tests were carried out at zero to 240 V. The results showed that at 200 V, the EMC were 85.71, 80.50, 88.23, 85.31, 94.71, 94.70, 90.68, and 83.3% for ACB, AOB, BCB, BOB, CCB, COB, DCB, and DOB, respectively. The respective ES are 23, 31, 25, 43, 98, 61, 98, and 65%. At 200 V, okra product CCB had the highest EMS and ES (94 and 98%, respectively). At 95% oil (w/o) emulsion, EMC for PRE and gelatin were 6.0 and 1.9%, respectively. At 5% oil (o/w) emulsion, the corresponding EMS and ES is 84 and 94%. Hydrolyzed okra seed PRE-CCB is possibly a hydrophilic emulsifier, combining high (94%) EMC with high (98%) ES.  Key words: Okra seed, protein-rich extract, hydrolysis, emulsification, electric field.